Travel-Time and Amplitude Sensitivity Kernels
Abstract
LONG-TERM GOALS: Our long-term goal is to study the sensitivity behavior of travel-time and arrival-amplitude observables due to sound-speed perturbations in low-frequency, long-range acoustic propagation in the ocean. OBJECTIVES: The leading objective of this project is to rigorously study the asymptotic behavior of wave-theoretic travel-time sensitivity kernels with increasing range, as a means to explain their observed convergence towards the corresponding ray-theoretic sensitivity kernels even at low frequencies. Further objectives include the derivation and study of 2D and 3D first-order amplitude sensitivity kernels, as well as vertical sensitivity kernels for arrival amplitudes, first- and second-order. A last objective is the study of sensitivity behavior of late arrivals depending on propagation frequency and range. APPROACH: Previous work has revealed a numerical convergence of wave-theoretic travel-time vertical sensitivity kernels (VTSKs) towards the corresponding ray-theoretic sensitivity kernels with increasing range even at low frequencies [1]. To study this behavior, the asymptotic form of finite-frequency kernels with increasing range is rigorously derived here using a stationary-phase approach [2]. The wave-theoretic VTSK involves an integral over frequency with a rapidly oscillating kernel, the oscillation rate increasing with propagation range. The stationary-phase approach is used to evaluate the asymptotic form of this integral and finally of the VTSK for long ranges.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2011
- Accession Number
- ADA571772
Entities
People
- Bruce D. Cornuelle
- Emmanuel Skarsoulis
- Matthew A. Dzieciuch
Organizations
- Scripps Institution of Oceanography